/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 26727
 * Date: 2024-06-30
 * Time: 15:03
 */
class Solution {
    int m,n,count;
    boolean[][] visit;
    int[] dx = {1,-1,0,0};
    int[] dy = {0,0,-1,1};

    public int maxAreaOfIsland(int[][] grid) {
        m = grid.length;
        n = grid[0].length;
        visit = new boolean[m][n];
        int ret = 0;
        for(int i = 0; i < m; i++) {
            for(int j = 0; j < n; j++) {
                if(!visit[i][j] && grid[i][j] == 1) {
                    count = 0;
                    dfs(grid,i,j);
                    ret = Math.max(ret,count);
                }
            }
        }
        return ret;
    }

    void dfs(int[][] grid,int i,int j) {
        visit[i][j]  = true;
        count++;

        for(int k = 0; k < 4; k++) {
            int x = i + dx[k],y = j + dy[k];
            if(x >= 0 && x < m && y >= 0 && y < n && !visit[x][y] && grid[x][y] == 1) {
                dfs(grid,x,y);
            }
        }
    }
}
